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The tern bulletin 



semblances are only superficial and a few minutes 

 given to learning their differences will make any col- 

 lector able to recognize either species at a glance. 



In the field N. patens is absolutely distinguished 

 from the plants that resemble it by its creeping root- 

 stock with the fronds arranged along it in two rows. 

 N. molle has an erect rootstock and the fronds in a 

 crown. In the herbarium, where often one has no 

 rootstock to aid in the identification, dependence must 

 be placed upon the venation. In N. patens the veins 

 are simple and the lowest pair meet at, or just below, 

 the sinus. In N. molle the lowest pair of veins meet 

 at some distance from the sinus, forming narrow 

 areolae and sending a single vein to the sinus. The 

 two types are well shown in our illustration. 



There has recently been reported from Florida a 

 third species belonging to this group named N. stipu- 

 late This differs from N. molle in having the lowest 

 pair of veins free or running together to the sinus and 

 from N'. patens by its more or less erect rootstock. 

 This latter characteristic does not seem to be constant 

 for there is one variety named pseudo patens indicating 

 how closely the two are connected. A variant form of 

 N. patens can thus be more easily mistaken for N. 

 molle and all reported occurrences of A r . stipulate 

 should be investigated with more than usual care. 



Fern students are in need of a careful mapping of 

 the range of N. patens and N. molle and we suggest 

 that all who have collected either of these species, re- 

 examine them and send us any new data thus obtained. 



